The global demand for energy continues to rise while reserves of conventional petroleum (e.g. oil, gas, and natural gas liquids) are in decline. A peak in oil production imposed by dwindling petroleum reserves raises the possibility of a global energy crisis, particularly if the demand for energy continues to rise as predicted. Hence, there is increased focus on the exploitation of previously unconventional fuel resources (e.g. heavy oil, oil sands, oil shale) and other non-fossil sources of energy (e.g. lignocellulosic materials).
A significant amount of research in the field of “alternative” energy production has focussed on the generation of biofuels from lignocellulosic matter. This technology raises the prospect of a shift to an abundant and renewable feedstock for energy production as an alternative to the depleting reserves of hydrocarbon-based raw materials. The enrichment of low energy density fossil fuels (e.g. lignite, peat and oil shale) into high energy fuel products also represents an attractive alternative given the relative abundance of those resources.
Despite having considerable potential most techniques for the production of fuels from lignocellulosic matter or other non-conventional materials are poorly cost-efficient and/or fail to provide fuel products of adequate quality to be commercially viable. For example, current processes for the production of biofuels from lignocellulosic matter usually require separation of the substrate into various different components via a series of complex and time-consuming steps, and in many cases require the use of expensive hydrolytic enzymes and fermenting microorganisms. In addition to these disadvantages, currently available processes fail to utilise a significant proportion of the substrate material which is not converted into fuel and goes to waste. Moreover, the fuels produced by current processes typically comprise a significantly higher oxygen content than conventional fuels. Hence, their energy density is comparatively low and their poor stability makes processing (e.g. storage, blending with conventional fuels, upgrading) difficult.
A need exists for improved methods of producing biofuels from organic matter that avoid one or more of the disadvantages stated above.